The present invention relates to a device for setting camera input data such as an exposure mode, a shutter speed, aperture value, film sensitivity and exposure factor for a still camera such as a single-lens reflex camera.
In order to control the exposure of a single-lens reflex camera, four exposure control methods, namely, an aperture-priority automatic exposure control method, a shutter-speed-priority automatic exposure control method, a programmed automatic exposure control method, and a manual exposure control method have heretofore been employed.
In order to perform aperture-priority automatic exposure, first a mode selector dial is set at an aperture-priority position, and then the lens aperture ring is turned to obtain the desired aperture value. In order to perform shutter-speed-priority automatic exposure, the lens aperture ring is locked at an automatic aperture position, and the mode selector dial is set at a desired shutter speed position. In order to perform programmed automatic exposure, the lens aperture ring is set at the automatic aperture position, and the setting dial is turned to a programmed automatic position. Finally, in order to perform manual exposure, the setting dial is set at a desired shutter speed position, and the lens aperture ring is turned from the automatic position to a desired aperture value.
In general, the mode selector dial has, in addition to the above-described four photographic mode positions, a bulb mode position to permit bulb or electronic flash photographing operations.
The above-described conventional camera suffers from a difficulty that errors are liable to occur in setting the exposure mode. For instance, when it is required to perform a photographing operation in the shutter-speed-priority automatic exposure mode, if the mode selector dial is mistakenly set to the "bulb" position with the lens aperture ring set at the automatic aperture position, the shutter speed will be incorrect and the exposure consequently not correct. There is also the difficulty that the lens aperture ring may be turned from the automatic aperture position and the camera operated in the manual exposure mode when the operator believes that the setting dial had been set to a desired shutter speed and the camera operated in the shutter-speed-priority automatic exposure mode. In this case also, the exposure will not be correct.